REACT JS：映射要在 JSX 中呈现的对象数组答案

【问题标题】：REACT JS: Map over an array of objects to render in JSXREACT JS：映射要在 JSX 中呈现的对象数组
【发布时间】：2016-08-25 16:24:29
【问题描述】：

我是 React JS 的新手问题是我需要在这段代码中显示我数据库中的所有字段。我已经能够在浏览器控制台中以对象的形式获取所有数据，并且能够在浏览器中查看数组中的最后一条数据，但无法查看它们。请原谅我的代码格式错误，因为我是新手。在此先感谢.....

输出和代码

浏览器视图： Land of Toys Inc. 是名称 131 是 ID

JSON 数据：

{"posts":[
  {"id":"103","name":"Atelier graphique"},
  {"id":"112","name":"Signal Gift Stores"},
  {"id":"114","name":"Australian Collectors, Co."},
  {"id":"119","name":"La Rochelle Gifts"},
  {"id":"121","name":"Baane Mini Imports"},
  {"id":"124","name":"Mini Gifts Distributors Ltd."},
  {"id":"125","name":"Havel & Zbyszek Co"},
  {"id":"128","name":"Blauer See Auto, Co."},
  {"id":"129","name":"Mini Wheels Co."},
  {"id":"131","name":"Land of Toys Inc."}
]}

此数据是通过编写为插件的 PHP 代码获得的，该插件采用 JS 代码中给出的 url 形式

http://localhost/Akshay/REACT/testDataAPI.php?user=2&num=10&format=json

我的代码：

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>React Tutorial</title>
    <!-- Not present in the tutorial. Just for basic styling. -->
    <link rel="stylesheet" href="css/base.css" />
    <script src="https://npmcdn.com/react@15.3.0/dist/react.js"></script>
    <script src="https://npmcdn.com/react-dom@15.3.0/dist/react-dom.js"></script>
    <script src="https://npmcdn.com/babel-core@5.8.38/browser.min.js"></script>
    <script src="https://npmcdn.com/jquery@3.1.0/dist/jquery.min.js"></script>
    <script src="https://npmcdn.com/remarkable@1.6.2/dist/remarkable.min.js"></script>
  </head>
  <body>
    <div id="content"></div>

    <script type="text/babel">


var UserGist = React.createClass({
  getInitialState: function() {
    return {

      username:[],
      companyID:[]
    };
  },

  componentDidMount: function() 
  {

    var rows = [];

   this.serverRequest = $.get(this.props.source, function (result) {

      for (var i=0; i < 10; i++) 
      {
            var lastGist = result.posts[i];
            //console.log(result.posts[i]);
            this.setState({
            username: lastGist.id,
            companyID: lastGist.name
            });
      }

     }.bind(this));

  },

  componentWillUnmount: function() {
    this.serverRequest.abort();
  },

  render: function() {
            return (
        <li>{this.state.companyID} is the name {this.state.username} is the ID</li>
        );

  }
});


ReactDOM.render(
  <UserGist source="http://localhost/Akshay/REACT/testDataAPI.php?user=2&num=10&format=json" />,
  document.getElementById('content')
); 

    </script>
  </body>
</html>

【问题讨论】：

标签： javascript php jquery json reactjs

【解决方案1】：

使用地图呈现您的数据。并将 json 作为 javascript 对象存储在状态本身而不是两个单独的数组中。

 <!-- Not present in the tutorial. Just for basic styling. -->
    <link rel="stylesheet" href="css/base.css" />
    <script src="https://npmcdn.com/react@15.3.0/dist/react.js"></script>
    <script src="https://npmcdn.com/react-dom@15.3.0/dist/react-dom.js"></script>
    <script src="https://npmcdn.com/babel-core@5.8.38/browser.min.js"></script>
    <script src="https://npmcdn.com/jquery@3.1.0/dist/jquery.min.js"></script>
    <script src="https://npmcdn.com/remarkable@1.6.2/dist/remarkable.min.js"></script>
    <div id="content"></div>

    <script type="text/babel">


var UserGist = React.createClass({
  getInitialState: function() {
    return {

     data: [{"id":"103","name":"Atelier graphique"},
  {"id":"112","name":"Signal Gift Stores"},
  {"id":"114","name":"Australian Collectors, Co."},
  {"id":"119","name":"La Rochelle Gifts"},
  {"id":"121","name":"Baane Mini Imports"},
  {"id":"124","name":"Mini Gifts Distributors Ltd."},
  {"id":"125","name":"Havel & Zbyszek Co"},
  {"id":"128","name":"Blauer See Auto, Co."},
  {"id":"129","name":"Mini Wheels Co."},
  {"id":"131","name":"Land of Toys Inc."}]
    };
  },

  componentDidMount: function() 
  {

  },

  componentWillUnmount: function() {
    this.serverRequest.abort();
  },

  render: function() {
            return (
            <div>
        {this.state.data.map(function(item, index){
          return    <li>{item.name} is the company name, {item.id} is the ID</li>

        })}</div>
        );

  }
});


ReactDOM.render(
  <UserGist source="http://localhost/Akshay/REACT/testDataAPI.php?user=2&num=10&format=json" />,
  document.getElementById('content')
); 

    </script>
</html>

JSFIDDLE

对于小提琴示例，我删除了 componentDidMount 中的 $.get() 代码。

附：将状态数组数据创建为对象数组，如小提琴示例

【讨论】：

我尝试使用 map 来渲染它，但它创建了一个错误，说它是未定义的，这会破坏您的解决方案并回复您，感谢您的帮助
@AkshayVenugopal 什么是未定义的
它可以工作，但我需要像 API 一样使用它，所以我应该如何处理这里的 JSON 数据在代码中给出，我需要从像 phpmyadmin 这样的数据库中使用它
同时弹出警告
"警告：数组或迭代器中的每个子节点都应该有一个唯一的"key" prop。检查UserGist. in li (UserGist 创建) in UserGist 中的渲染方法"

【解决方案2】：

我想它会帮助你。

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>React Tutorial</title>
    <!-- Not present in the tutorial. Just for basic styling. -->
    <link rel="stylesheet" href="css/base.css" />
    <script src="https://npmcdn.com/react@15.3.0/dist/react.js"></script>
    <script src="https://npmcdn.com/react-dom@15.3.0/dist/react-dom.js"></script>
    <script src="https://npmcdn.com/babel-core@5.8.38/browser.min.js"></script>
    <script src="https://npmcdn.com/jquery@3.1.0/dist/jquery.min.js"></script>
    <script src="https://npmcdn.com/remarkable@1.6.2/dist/remarkable.min.js"></script>
  </head>
  <body>
    <div id="content"></div>

    <script type="text/babel">


var UserGist = React.createClass({
  getInitialState: function() {
    return {

      username:[],
      companyID:[]
    };
  },

  componentDidMount: function() 
  {

    var rows = [];

   this.serverRequest = $.get(this.props.source, function (result) {
      var username = [];
      var companyID = [];
      for (var i=0; i < 10; i++) 
      {
            var lastGist = result.posts[i];
            //console.log(result.posts[i]);
            username.push(lastGist.id);
            companyID.push(lastGist.name);
      }
      this.setState({
            username: username,
            companyID: companyID,
      });
     }.bind(this));

  },

  componentWillUnmount: function() {
    this.serverRequest.abort();
  },

  render: function() {
      return (
        <div>
    {this.state.companyID.map(function(item, index){
      return    <li>{item} is the company name,              {this.state.username[index]} is the ID</li>
    })}</div>
        );

  }
});


ReactDOM.render(
  <UserGist source="http://localhost/Akshay/REACT/testDataAPI.php?user=2&num=10&format=json" />,
  document.getElementById('content')
); 

    </script>
  </body>
</html>

【讨论】：

TypeError: 这是未定义的 singleList() render() browser.min.js%20line%203%20%3E%20Function:52 [36]() react.js: 6614 [36]() react.js:6641 [36]()
你能给出错误的描述吗？行号：？？？让我看看。
不看。我已经编辑过了。希望它会起作用。